Hex #559539 or rgb(85,149,57) in RGB space is the tint of grass green. It has hue angle of 101.74 degrees, value = 58 and saturation = 62. #559539 can be obtained by mixing 4 colors: 2 drops of yellow, 1 drop of magenta, 2 drops of blue, 4 drops of green.
Nearest safe hex - #669933. Below you can see the block with #559539 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #559539 to the mixer and play with it.